Source: Investopedia
前言：Jane Street 是玩高頻交易 (High-Frequency Trading, HFT) 的美資狙擊手，近年被印度和中國的金融監管機構盯上，用行政手段打壓。表面上的原因是涉嫌操縱市場 (Market Manipulation) ，咖哩版加上逃税。真正原因是其運作模式頗具殺傷力，可以導致金融市場突然大幅波動，國產中文的說法是「影響金融安全」，即是透過在金融市場興波作浪動搖政權。
以下提供的參考資料有助讀者了解什麼是高頻交易 (HFT)，其優點和缺點及風險（依賴高效能的電腦系统），還有印度和中國的金融監管機構的回應。至於香港的金融監監管機構會怎樣回應，是否會跟隨中國的做法，有待觀察。
天下武功，唯快不破？龍象 vs 美資，值得留意。
延伸閱讀／參考資料：
Jane
Street's India Scandal: Is the World's Biggest Market Rigged?
By
Tom Wright
Whale
Hunting
Aug 11, 2025
Intro: Indian regulators are widening a probe into secretive trading firm Jane Street, launching an investigation into whether the firm and other foreign high-frequency traders gained an unfair advantage through privileged access to proprietary trading data.
At Whale Hunting, we investigate the hidden engines of global finance. Our latest story goes far beyond the headlines to reveal how one of the world's most powerful and secretive trading firms is at the center of a mounting scandal in India.
Yes, we're talking about Jane Street – the same firm that trained disgraced crypto kingpin Sam Bankman-Fried and, by some estimates, accounts for over 10% of all North American equity market activity. Now, as Indian regulators probe allegations of market manipulation and privileged access to trading data, the firm’s extraordinary profits are under the microscope.
This is a battle for the soul of a nation's fast-growing financial system, pitting the technological might of foreign firms against the millions of local investors who are consistently losing out. Can India protect its markets from a new kind of "predatory" capital, or is this a global game of whack-a-mole that regulators are destined to lose?
（推介原因：Jane Street 的商業模式是透過高頻交易 (High-Frequency Trading, HFT) 獲利。該公司在覓食市場只會維持一個小規模的辦事處，即是有心理準備當地的監管機構會上門掃蕩或透過行政手段找麻煩。外資撤離中國，部份跨國企業的供應鏈轉移至印度。印度經濟因此得益，成為美資狙擊手的最新目標，而香港和新加坡其實是遠距離操控高頻交易的據點。為免印度的經濟成就被美式金融掠食者所掠奪或摧毀，印度的監管機構出手對付 Jane Street，表面上的理由，是操縱市場和逃稅。Jane Street 在香港開設據點，並非好事。證明香港是國際金融中心？哈哈。特區政府的財金官員是否明白個中玄機，又是另一個問題。）
（作者 Tom Wright 是獨立網媒 Whale Hunting 的其中一位創辦人，另一位創辦人是 Bradley Hope，二人是前華爾街日報記者，擅長調查報導，之後創立網媒 Whale Hunting。）
Wikipedia: Jane Street Capital
https://en.wikipedia.org/wiki/Jane_Street_Capital
Excerpt: Jane Street Capital is an American proprietary trading firm headquartered in New York City. It employs more than 2,600 people in six offices in New York City, London, Hong Kong, Amsterdam, Chicago, and Singapore, and trades a broad range of asset classes on more than 200 venues in 45 countries.
It is among the principal market-makers – in 2020 it traded more than $17 trillion worth of securities. It was considered to have helped keep bond exchange-traded funds (ETFs) liquid during the market turmoil in 2020.
History
Jane Street was co-founded by Tim Reynolds, Rob Granieri, Marc Gerstein, and Michael Jenkins. Reynolds, Granieri, and Jenkins were formerly traders at Susquehanna International Group. It was started in 1999. In 2012, Tim Reynolds stepped down from his position running the firm.
Activities
The firm ended 2020 having traded $4 trillion in global equities, $1.4 trillion in bonds, and $3.9 trillion in ETFs. During the COVID-19 pandemic, the firm saw its revenue jump 54% to a record of $10.6 billion during the year ended in March 2021.
As of 2021, its trading capital was about $15bn. As well as high-frequency trading（高頻交易）, it in some cases maintained positions for hours, even days or sometimes weeks, which is essential for ETFs that track less-traded markets. On any given day, it was holding about $50bn of securities. It is an authorised participant in 2,600 ETFs and lead market-maker on 506 ETFs, and plays an important role in maintaining ETF liquidity.
In 2023, the company generated $10.6bn in net trading revenue with adjusted earnings of $7.4bn. It released these numbers as part of a debt deal which aimed to expand the amount of cash on Jane Street's balance sheet from $4.3bn to $5.6bn.
In June 2025, Jane Street co-founder Robert Granieri funded an alleged coup d'état plot to topple the government of South Sudan. Granieri claimed he was duped into funding the alleged coup plot, helping Peter Biar Ajak purchase Stinger missiles, AK-47s, and grenades.
In July 2025, Indian stock market regulator SEBI accused Jane Street Capital of a "sinister scheme", seized over 550M in "illegal gains" and has issued a freeze on the firm's activities in India, a country where the firm had recorded 2B in profits over approximately the last two years, as a deeper probe is conducted. Jane Street Capital has asserted its innocence in the face of the allegations. SEBI alleges that Jane Street Capital was engaged in market manipulation in the form of an "intra-day index manipulation strategy", in which Jane Street took long positions in BANKNIFTY index and its constituent stocks through cash and futures, in the first half of the trading sessions on option expiry days, while simultaneously taking much larger short positions through options. After dumping the long position in the index and constituent stocks in the second half of the session and taking a loss on those trades, it profited many times more on the options trade. SEBI also claimed that Jane Street created circular trades between itself and its India-registered entities, as part of the strategy.
Technology
Almost all of its software is written in the OCaml programming language. Their repository is around 70 million lines long.
Scandals
India derivatives market scam (2025)
In July 2025, the Securities and Exchange Board of India (SEBI) issued an interim ban barring Jane Street and its affiliated entities from trading in Indian securities markets, citing alleged expiry‑day manipulation of the Bank Nifty index using coordinated cash, futures, and options trades. SEBI froze approximately ₹48,43 billion (US $567 million) in purported trading profits, described as "unlawful gains". Jane Street complied with the order by depositing the amount into escrow but has formally contested SEBI’s characterization, asserting its actions represented legitimate index arbitrage.
After the escrow deposit, SEBI lifted the trading restrictions. Jane Street, however, did not resume trading, citing prior commitments not to trade in options—a key part of its strategy. SEBI's investigation expanded to examine six of its affiliated entities and trading records spanning from January 2023 to May 2025.
India’s Income Tax Department also initiated document reviews of Jane Street’s local operations and its partner firm, Nuvama Wealth, to investigate possible violations of tax treaty provisions and anti‑avoidance rules. Reports indicate that Jane Street maintains critical accounting infrastructure offshore, with minimal local staffing in India.
The incident significantly affected the Indian derivatives market, resulting in a marked decline in Bank Nifty options turnover. SEBI chair Tuhin Kanta Pandey has since called for structural reforms to enhance market fairness and protect retail investor interests. Jane Street continues to deny any wrongdoing and plans to respond formally to SEBI’s allegations within regulatory timelines.
Notable past employees
Sam Bankman-Fried (薯條哥) and Caroline Ellison, recipients of misappropriated FTX customer funds, were once employed by the company.
Brett Harrison, current CEO of trading technology firm Architect Financial Technologies
Zvi Mowshowitz, writer who covers topics in artificial intelligence
Ophelia Bauckholt, deceased quantitative trader associated with the Zizian rationalists, interned at Jane Street as an undergrad.
（推介原因：印度的金融監管機構怎樣對付 Jane Street 以及該公司最著名的前員工。能夠訓練出國際級金融騙子「薯條哥」，不可能是善男信女，對不對？熟悉財經新聞的讀者應該記得，「薯條哥」的父母在美國的大學教法律。法律人才教出國際級金融騙子，說明現實比小說更離奇。）
Investopedia
Understanding High-Frequency Trading (HFT):
Basics, Mechanics, and Example
By James Chen
Updated August 10, 2025
https://www.investopedia.com/terms/h/high-frequency-trading.asp
Excerpt: What Is High-Frequency Trading
(HFT)?
High-frequency trading (HFT) leverages
advanced computer programs and sophisticated algorithms to execute vast numbers
of orders in mere fractions of a second. These algorithms rapidly analyze
numerous markets and respond to varying market conditions to execute trades
efficiently. Having the fastest execution speeds allows traders and financial
institutions to capitalize on minimal price discrepancies for higher
profitability, which distinguishes HFT through elevated turnover rates and
order-to-trade ratios.
Key Points:
- High-frequency trading (HFT) uses sophisticated computer programs to execute a vast number of trades in mere fractions of a second, offering significant advantages in speed and efficiency.
- HFT has improved market liquidity and narrowed bid-ask spreads, though its controversial nature raises concerns about market stability and fairness.
- Famous HFT firms like Tower Research Capital and Virtu Financial leverage this technology to capitalize on arbitrage opportunities and rapid market movements.
- Critics argue that HFT can result in significant market disruptions, as evidenced by the 2010 "Flash Crash," and that it offers large institutions an advantage over smaller traders.
- HFT has extended into the cryptocurrency market, offering the same speed and efficiency benefits while also posing similar risks.
The Mechanics of High-Frequency
Trading Explained
High-frequency trading is a type of algorithmic trading. Traders are able to use HFT when they analyze important data to make decisions and complete trades in a matter of a few seconds. HFT facilitates large volumes of trades in a short amount of time while keeping track of market movements and identifying arbitrage opportunities.
Some of the key characteristics of high-frequency trading include:
- Trading at high speeds
- A large number of transactions executed
- Short-term investment horizons
Because of the complexities and intricacies involved with HFT, it isn't surprising that it is commonly used by banks, other financial institutions, and institutional investors.
HFT gained popularity when exchanges offered incentives for companies to add market liquidity. For instance, the New York Stock Exchange (NYSE) has a group of liquidity providers called supplemental liquidity providers (SLPs) that attempt to add competition and liquidity for existing quotes on the exchange.
The SLP was introduced following the collapse of Lehman Brothers in 2008, when liquidity was a major concern for investors. As an incentive to companies, the NYSE pays a fee or rebate for providing said liquidity. Millions of daily transactions generate substantial profits.
Assessing the Pros and Cons of High-Frequency Trading
Advantages
The main benefit of high-frequency trading is the speed and ease with which transactions can be executed. Banks and other traders are able to execute a large volume of trades in a short period of time—usually within seconds.
HFT has improved market liquidity and eliminated very small bid-ask spreads. This was tested by adding fees on HFT, which led to an increase in bid-ask spreads. One study assessed how Canadian bid-ask spreads changed when the government introduced fees on HFT. It found that market-wide bid-ask spreads increased by 13% and retail spreads increased by 9%.
Disadvantages
HFT is controversial and has been met with some harsh criticism. It has replaced a number of broker-dealers and uses mathematical models and algorithms to make decisions, taking human decisions and interaction out of the equation.
Decisions happen in milliseconds, and this could result in big market moves without reason. For example, on May 6, 2010, the Dow Jones Industrial Average (DJIA) experienced its largest intraday drop, falling 1,000 points and 10% in 20 minutes before recovering. A government investigation blamed a massive order that triggered a sell-off for the crash.
Another critique of HFT is that it benefits
large companies often at the expense of smaller traders. Its so-called ghost
liquidity is also a source of criticism: The liquidity provided by HFT is
available to the market one second and gone the next, preventing traders from
actually being able to trade this liquidity.
Pros
- Large volume of transactions at once
- Easy and speedy process
- Improves market liquidity
- Removes small bid-ask spreads
Cons
- Removes human decision making and interaction
- Speedy transactions could result in major market moves
- Traders can’t trade liquidity
How Fast Is a High-Frequency Trade?
High-frequency trading is fast. It can be as fast as 10 milliseconds. In some cases, it can be even less to execute a large batch of trades.
The Bottom Line
Advances in technology have helped many parts of the financial industry evolve, including the trading world. Computers and algorithms have made it easier to locate opportunities and make trading faster. High-frequency trading allows major trading entities to execute big orders very quickly.
Although it makes things easier, HFT (and other types of algorithmic trading) does come with
drawbacks—notably the danger of causing major market moves, as it did in 2010,
when the Dow suffered a large intraday drop.
Investopedia
Unveiling High-Frequency Trading:
Strategies, Secrets, and Key Players
By Prableen Bajpai
Updated October 26, 2025
Excerpt: High-frequency trading (HFT) dominates U.S. and European financial markets. It uses advanced algorithms to execute trades in fractions of a second. HFT firms gain an edge through speed, technology, strategic planning, and often keeping their tactics secret. Common strategies include arbitrage, directional trading, and market-making, which aim to profit from tiny price movements. While HFT can boost market liquidity, it also carries risks and ethical concerns, such as market manipulation and unfair advantages over traditional traders.
Key Points
- HFT firms execute trades in microseconds, using powerful algorithms for rapid transactions.
- Strategies include arbitrage, market making, and short-term directional trading for profit.
- HFT firms provide market liquidity, reducing bid-ask spreads, but face volatility risks.
- Major HFT players include Citadel
Securities, Virtu Americas, and Jane Street Capital.
- While HFT is largely legal, practices like market manipulation remain prohibited.
（推介原因：同上。）
Jane Street to pay US$3.9m a month for Hong Kong seafront offices in record-setting lease
The trading firm takes a 223,000 sq ft
space in one of the largest leasing transactions in Central in decades
Cheryl Arcibal
SCMP (13 Jun 2025)
Excerpt: Henderson Land Development, one of Hong Kong’s largest developers, has leased a 223,437 sq ft space in its prized mixed-use project in Central to Jane Street Asia in one of the largest leasing transactions in the city’s main business district in decades.
The rent for the space, across six floors in New Central Harbourfront, will be HK$137 (US$17.45) per square foot per month, or HK$30.6 million per month, excluding fees. The transaction, which makes the quant trading firm the anchor tenant of the development, is equivalent to 70 per cent of the office and ancillary portion of the first phase of the project. “We are proud to welcome Jane Street to our New Central Harbourfront flagship development project,” said Martin Lee Ka-shing, chairman of Henderson Land.
（推介原因：Jane Street 會在香港待多久，有待觀察。）
Jane Street – Who we are
https://www.janestreet.com/who-we-are/
Excerpt: Established in 2000. Evolving ever since.
We were founded by a small group of traders and technologists in a tiny New York office. Today, we have more than 3000 employees across five global offices. We trade a broad range of asset classes on more than 200 venues in 45 countries. We innovate in tech, from functional programming to machine learning to programmable hardware. And while our proprietary trading business thrives, we put our expertise and experience to work for our clients.
Taking on the most difficult trading challenges
Markets are defined by uncertainty. This is why quantitative thinking is crucial for our business. At Jane Street, we emphasize understanding the edge cases and tail risks that others overlook, and that matter most when markets deviate from expectations. We hire researchers and traders whose ideas and algorithms are informed by a deep mathematical fluency, and technologists who understand their systems from the hardware on up. We understand individual products and the context that informs their prices down to their subtlest details. This allows us to provide liquidity during the market’s most volatile moments.
Jane Street – What We Do
https://www.janestreet.com/what-we-do/overview/
Excerpt: We are a global liquidity provider and trading firm that uses sophisticated quantitative analysis and a deep understanding of market mechanics to help keep prices consistent and reliable.
At Jane Street, our work blends human intuition — earned through more than twenty years of experience — with cutting-edge research. Our style is both rigorous and pragmatic. Depending on the problem, we might draw on large-scale machine learning, domain expertise, or pen-and-paper mathematics. We’re a firm of puzzle solvers on and off the clock.
Technical to the core.
Technology is central to everything we do. Twenty years of using the most advanced tools available and applying them to complex problems at market scale has given Jane Street a reputation of technical excellence.
We build almost all of our software in-house, including our critical trading and risk management systems, using a statically typed functional programming language called OCaml. Although we prize automation, human judgment and insight are critical to how we trade. We’ve invested heavily in sourcing and building tools that provide traders with real-time visibility and insight into our trading activity to help guide their decision making.
（推介原因：Jane Street 的自述。）
China Clamps Down on High-Speed Traders,
Removing Servers
Bloomberg
January 16 2026
Key Points:
- China is removing servers dedicated to high-frequency traders from local exchanges' data centers, a move led by regulators that will affect both domestic and global firms.
- The change will impact the speed advantage that high-frequency traders have used to beat rivals, as they will no longer be able to get slightly quicker execution by using servers located in the exchanges' own data centers.
- Futures exchanges have made preliminary plans to add latency to any servers that connect from third-party computer rooms, which will further reduce the speed advantage of high-frequency traders.
（推介原因：繼印度之後，中國的金融監管機構出手對付高頻交易，以免被玩這一套的美資狙擊手「影響金融安全」，即是透過在金融市場興波作浪動搖政權。香港的金融監管機構是否會跟隨，有待觀察。）
China Weights Tenfold Fee Increase on High
Frequency Traders
Bloomberg
July 26 2024
Key Points:
- Regulators consult some firms to gauge impact, people say
- Officials have pledge to slow such traders by weighting costs
（推介原因：相關的報導。中國的金融監管機構在 2024
年 7 月底已經開始對付玩高頻交易的美資狙擊手，證明金融市場是中美關係的其中一個戰場。）
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